How to find out the size of the bearing?

How to buy a bearing with no marking? This question is asked not each of you. Here are some tips on how to find out the size of the bearing and the bearing  itself. We will show on an example of a ball bearing.

First, we measure the internal diameter (30 mm) with a calipers.

Now the outer diameter (72 mm).

And, of course, the width of the bearing (19 mm).

Thanks to the parameters it is possible to pick up a bearing by size. Enter them on the website in the section "Parameters". Fill the type of seal, in our case - plastic on both sides.